diff options
Diffstat (limited to 'drivers/watchdog/mena21_wdt.c')
| -rw-r--r-- | drivers/watchdog/mena21_wdt.c | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/drivers/watchdog/mena21_wdt.c b/drivers/watchdog/mena21_wdt.c new file mode 100644 index 000000000..96dbba980 --- /dev/null +++ b/drivers/watchdog/mena21_wdt.c @@ -0,0 +1,270 @@ +/* + * Watchdog driver for the A21 VME CPU Boards + * + * Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation + */ +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> +#include <linux/uaccess.h> +#include <linux/gpio.h> +#include <linux/of_gpio.h> +#include <linux/delay.h> +#include <linux/bitops.h> + +#define NUM_GPIOS 6 + +enum a21_wdt_gpios { + GPIO_WD_ENAB, + GPIO_WD_FAST, + GPIO_WD_TRIG, + GPIO_WD_RST0, + GPIO_WD_RST1, + GPIO_WD_RST2, +}; + +struct a21_wdt_drv { + struct watchdog_device wdt; + struct mutex lock; + unsigned gpios[NUM_GPIOS]; +}; + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv) +{ + int reset = 0; + + reset |= gpio_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0; + reset |= gpio_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0; + reset |= gpio_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0; + + return reset; +} + +static int a21_wdt_start(struct watchdog_device *wdt) +{ + struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); + + mutex_lock(&drv->lock); + + gpio_set_value(drv->gpios[GPIO_WD_ENAB], 1); + + mutex_unlock(&drv->lock); + + return 0; +} + +static int a21_wdt_stop(struct watchdog_device *wdt) +{ + struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); + + mutex_lock(&drv->lock); + + gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0); + + mutex_unlock(&drv->lock); + + return 0; +} + +static int a21_wdt_ping(struct watchdog_device *wdt) +{ + struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); + + mutex_lock(&drv->lock); + + gpio_set_value(drv->gpios[GPIO_WD_TRIG], 0); + ndelay(10); + gpio_set_value(drv->gpios[GPIO_WD_TRIG], 1); + + mutex_unlock(&drv->lock); + + return 0; +} + +static int a21_wdt_set_timeout(struct watchdog_device *wdt, + unsigned int timeout) +{ + struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); + + if (timeout != 1 && timeout != 30) { + dev_err(wdt->dev, "Only 1 and 30 allowed as timeout\n"); + return -EINVAL; + } + + if (timeout == 30 && wdt->timeout == 1) { + dev_err(wdt->dev, + "Transition from fast to slow mode not allowed\n"); + return -EINVAL; + } + + mutex_lock(&drv->lock); + + if (timeout == 1) + gpio_set_value(drv->gpios[GPIO_WD_FAST], 1); + else + gpio_set_value(drv->gpios[GPIO_WD_FAST], 0); + + wdt->timeout = timeout; + + mutex_unlock(&drv->lock); + + return 0; +} + +static const struct watchdog_info a21_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, + .identity = "MEN A21 Watchdog", +}; + +static const struct watchdog_ops a21_wdt_ops = { + .owner = THIS_MODULE, + .start = a21_wdt_start, + .stop = a21_wdt_stop, + .ping = a21_wdt_ping, + .set_timeout = a21_wdt_set_timeout, +}; + +static struct watchdog_device a21_wdt = { + .info = &a21_wdt_info, + .ops = &a21_wdt_ops, + .min_timeout = 1, + .max_timeout = 30, +}; + +static int a21_wdt_probe(struct platform_device *pdev) +{ + struct device_node *node; + struct a21_wdt_drv *drv; + unsigned int reset = 0; + int num_gpios; + int ret; + int i; + + drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL); + if (!drv) + return -ENOMEM; + + /* Fill GPIO pin array */ + node = pdev->dev.of_node; + + num_gpios = of_gpio_count(node); + if (num_gpios != NUM_GPIOS) { + dev_err(&pdev->dev, "gpios DT property wrong, got %d want %d", + num_gpios, NUM_GPIOS); + return -ENODEV; + } + + for (i = 0; i < num_gpios; i++) { + int val; + + val = of_get_gpio(node, i); + if (val < 0) + return val; + + drv->gpios[i] = val; + } + + /* Request the used GPIOs */ + for (i = 0; i < num_gpios; i++) { + ret = devm_gpio_request(&pdev->dev, drv->gpios[i], + "MEN A21 Watchdog"); + if (ret) + return ret; + + if (i < GPIO_WD_RST0) + ret = gpio_direction_output(drv->gpios[i], + gpio_get_value(drv->gpios[i])); + else /* GPIO_WD_RST[0..2] are inputs */ + ret = gpio_direction_input(drv->gpios[i]); + if (ret) + return ret; + } + + mutex_init(&drv->lock); + watchdog_init_timeout(&a21_wdt, 30, &pdev->dev); + watchdog_set_nowayout(&a21_wdt, nowayout); + watchdog_set_drvdata(&a21_wdt, drv); + + reset = a21_wdt_get_bootstatus(drv); + if (reset == 2) + a21_wdt.bootstatus |= WDIOF_EXTERN1; + else if (reset == 4) + a21_wdt.bootstatus |= WDIOF_CARDRESET; + else if (reset == 5) + a21_wdt.bootstatus |= WDIOF_POWERUNDER; + else if (reset == 7) + a21_wdt.bootstatus |= WDIOF_EXTERN2; + + ret = watchdog_register_device(&a21_wdt); + if (ret) { + dev_err(&pdev->dev, "Cannot register watchdog device\n"); + goto err_register_wd; + } + + dev_set_drvdata(&pdev->dev, drv); + + dev_info(&pdev->dev, "MEN A21 watchdog timer driver enabled\n"); + + return 0; + +err_register_wd: + mutex_destroy(&drv->lock); + + return ret; +} + +static int a21_wdt_remove(struct platform_device *pdev) +{ + struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev); + + dev_warn(&pdev->dev, + "Unregistering A21 watchdog driver, board may reboot\n"); + + watchdog_unregister_device(&drv->wdt); + + mutex_destroy(&drv->lock); + + return 0; +} + +static void a21_wdt_shutdown(struct platform_device *pdev) +{ + struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev); + + gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0); +} + +static const struct of_device_id a21_wdt_ids[] = { + { .compatible = "men,a021-wdt" }, + { }, +}; + +static struct platform_driver a21_wdt_driver = { + .probe = a21_wdt_probe, + .remove = a21_wdt_remove, + .shutdown = a21_wdt_shutdown, + .driver = { + .name = "a21-watchdog", + .of_match_table = a21_wdt_ids, + }, +}; + +module_platform_driver(a21_wdt_driver); + +MODULE_AUTHOR("MEN Mikro Elektronik"); +MODULE_DESCRIPTION("MEN A21 Watchdog"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:a21-watchdog"); |